Neutron decay is not a electromagnetic phenomena at all. It is governed by the weak nuclear force. This is well supported by fact that [the lifetime of the neutron][1] fits neatly into [weak universality][2].

Secondly the neutron is *not* it's own antiparticle. The anti-neutron is a distnct particle.


  [1]: http://physics.stackexchange.com/questions/31514/why-is-the-free-neutron-lifetime-so-long/31517#31517
  [2]: http://physics.stackexchange.com/questions/11664/universality-in-weak-interactions